Hello @StrawHatM23
Here is a sample code for you to start.
<script>
function setLang(lang){
const urlParams = new URL(window.location.href);
urlParams.searchParams.set('l', lang);
window.location.href = urlParams;
}
</script>
<%
var englishLang={text1:"Hello",text2:"World"};
var frenchLang={text1:"Bonjour",text2:"Monde"};
var selectedLang=ctx.vars.lang;
if(selectedLang == 'fr'){
var userLang=frenchLang;
}else{
var userLang=englishLang;
}
%>
<button onClick="setLang('en')">English</button>
<button onClick="setLang('fr')">French</button>
<%= userLang.text1 %> <%= userLang.text2 %>
You will have to add a parameter in WebApp properties with the name as l and then create a variable with name lang.